Over the past few years, various types of low profile electrical plugs have been developed, for use in conjunction with conventional 110 VAC electrical outlets or receptacles, such as those typically used in residential and commercial buildings. On particular reason for development of such low profile electrical plugs is to permit furniture to be placed immediately juxtaposed to a wall, or at least very close thereto, in front of an electrical outlet. Conventional profile electrical plugs extend outwardly from an electrical outlet for perhaps one inch to about two inches or more, and therefore often preclude a piece of furniture from being placed immediately juxtaposed to a wall. It follow that low profile electrical plugs having tabs to facilitate their removal from electric outlets are inherently safer, as there is no chance that the fingers of a user will contact the blades of the plug while they are still alive electrically.
One example of a low profile type electrical plug can be found in Dickie U.S. Pat. No. 4,927,376, which is commonly owned herewith. This low profile electrical plug has a main body that is about 1/4 inch thick, with the electrical wire coming out from one corner or end of the plug. Accordingly, it is necessary to utilize a pull ring as part of the electrical plug in order to remove the electrical plug from the outlet.
The pull ring is the subject matter of U.S. Pat. No. 5,057,036, which is also commonly owned herewith, and which teaches electrical plugs that are sold extensively throughout North America in association with the trademark FLATPLUG. The pull ring--which is formed from metal, for reasons of strength--is pivotally attached in a semi-permanent manner to the main body of the electrical plug, so as to preclude removal of the pull ring from the main body of the electrical plug during normal usage or by way of significant efforts directed at such removal. In other words, this pull ring arrangement is quite robust. The pivoting pull ring is fashioned with lock stubs bent at three serial right angles at each secured end of the pull ring, so as to be securely retained within respective co-operating lock stub cavities within the main body portion. A lock tab at each of the lock stub cavities partially defines the respective lock stub cavity and precludes the lock stub on the pull ring from being readily removed therefrom. During assembly of the electrical plug, the lock stub at each end of the pull ring deforms the respective lock tab to permit entry of the lock into the lock stub cavity. The lock tab is fashioned with a gradual ramp on the side away from the lock stub cavity to facilitate the gradual deformation of the lock tab as the lock stub is forced over the lock tab. Once the lock stub is in the lock stub cavity, the lock tab returns to its original position, which thereby locks the lock stub into the lock stub cavity. The side of the lock tab facing the lock stub cavity is fashioned with an abrupt vertical face which prevents the lock stub from deforming the lock tab from the lock stub cavity side, thereby permanently locking the lock stub into the lock stub cavity.
There are, however, some considerations surrounding the earlier type of pull ring, as used in conjunction with low profile electrical plugs. The main concern is that the electrical plug including the metal pull ring is relatively expensive to manufacture, especially since the pull ring must be relatively robust and it must be well anchored into the plug so that it cannot be readily removed. The metal pull ring must be first formed, then preferably coated with a tarnish and oxidation resistant outer coating, and then must be carefully and forcibly manipulated into place onto the main body of the electrical plug during the manufacturing operation. Moreover, the molding operation of the main body requires the use of moveable side cores in the mold, adding to the expense of making and operating the mold. Thus, this type of low profile electrical plug may be considered to be somewhat more expensive than is necessary for some applications.
It has been found that in electrical extension cords or appliance cords, the plugs of the extension cords may be plugged in and unplugged from the electrical outlet or receptacle only a few times--typically less than ten times--over the life of an extension cord or small appliance such as a high fidelity amplifier, television set, or floor lamp. Accordingly, in an extension cord comprising a low profile electrical plug, the ring or tab that is used to remove the electrical plug from an electrical outlet may not need to be as robust as other types of rings or tabs that might be used on electrical plugs on the electrical cord of perhaps a major electrical appliance such as a washer or refrigerator, sewing machine, microwave oven or the like, or a power tool. The pull tab or ring can potentially be made of the same molded plastic material as the main body of the electrical plug, so as to permit cost cutting at the manufacturing level.
A low-profile electrical plug having a molded plastic pull ring is disclosed in commonly owned U.S. Pat. No. 4,857,013 to Peters. As disclosed in this patent, the molded plastic pull ring may be integrally molded within the main body of the electrical plug so as to be bendable between a stored position against the main body and an in-use position whereat the molded plastic pull ring extends away from the main body. This particular configuration of integral molded plastic pull ring has a number of problems associated with it, including an unnecessarily large size of plug, and a tendency for the molded plastic pull ring to permanently bend or even break, as the shape hand orientation of the pull ring are not directed along the line of action of the pulling force when the electrical plug is being removed from an outlet. Alternatively, the molded plastic pull ring may be mechanically hinged onto the main body for movement between a stored position and an in-use position, as described above. This particular configuration of mechanically hinged plastic pull ring also has a number of problems associated with it including an unnecessarily large size of electrical plug, a tendency for the pull ring to pull out of the main body during use, and a tendency to be difficult and expensive to manufacture due to the inclusion of hinges.
It is an object of the present invention to provide an electrical plug having an integral molded plastic removal tab, which molded plastic low profile electrical plug is less expensive to manufacture than other types of molded plastic low profile electrical plugs.
It is an object of the present invention to provide an electrical plug having an integral molded plastic removal tab, that does not permanently deform as a result of use.
It is an object of the present invention to provide an electrical plug having an integral molded plastic removal tab, that does not readily break as a result of use.
It is an object of the present invention to provide an electrical plug having an integral molded plastic removal tab, that may not easily be pulled out of the main body as a result of regular use.